“A major risk”: how air pollution alters fetal development during pregnancy

There air pollution presents a major risk for the development of the unborn child. This is detailed by researchers from Inserm, the national institute of health and medical research, and the University of Grenoble Alpes, in a study released this Tuesday, May 7, 2024.

Placenta DNA potentially altered

They looked at how placental DNA is changed by exposure to three major air pollutants.

The placenta is an organ that plays a key role in fetal development. Particularly vulnerable to numerous chemical compounds, it can be compared to an “archive” testifying to the child’s prenatal environment: the epigenetic modifications occurring in its cells partly reflect the environmental exposures of the mother during pregnancy.

The researchers thus examined the impact of nitrogen dioxide and two types of fine particles on the DNA of the placenta, an organ which plays a key role in fetal development.

Results: these placental modifications (“placental epigenetic changes”) are likely to “alter the development of the fetus at the metabolic, immune and neurological levels”.

Differences depending on the sex of the unborn child

By comparing data from 1,500 French pregnant women, the study shows that the fetus is not impacted at the same time during pregnancy, depending on whether it is a boy or a girl to be born. And the impacts are not the same.

Exposure to outdoor air pollution presents a major risk for the successful progress of the pregnancy. It is particularly suspected of being the cause of cardio-metabolic, respiratory or even neuropsychological pathologies in the unborn child.

In boys: the genes affected particularly concern the development of the nervous system and the intellect.

In girls, the incidences could more concern the development of chronic metabolic diseases such as hypertension, diabetes, or obesity, or the occurrence of miscarriages or preeclampsia in the mother.

More and more studies

“These observations support the growing number of studies associating exposure to air pollution during pregnancy and impaired neurodevelopment and/or a reduction in cognitive abilities, with greater vulnerability of children of the same sex. masculine,” explains Lucile Broséus, cited by Inserm.

The fact remains that although these physiological effects have been studied, the molecular mechanisms at play are still poorly understood, the researchers admit.

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